One type of an electronic component mounting machine is a mounting machine as shown in FIG. 1 and FIG. 2, in which electronic components are supplied from component feed sections 2a, 2b fixed at determined positions, and the electronic components are mounted on a circuit board 3 set at a fixed position by a mounting head 4 composed to move freely in the X and Y directions.
Component feed sections in this type of electronic component mounting machine include component feed sections as shown in FIG. 2, in which a pair of confronting component feed sections 2a, 2b are disposed in the Y direction at an interval, and the X-direction position of each one of the component feed sections 2a, 2b is a component arrangement position p.
In the mounting machine having such component feed sections 2, the arrangement positions of electronic components were determined according to the flow of the prior art shown in FIG. 9.
That is, at step 51, data of all electronic components (including coordinates data of mounting position) to be mounted on a circuit board 3 is fetched. Next, at step 52, the fetched data is sorted into every kind of electronic components based on the name and shape code. At step 53, the electronic components of every kind are rearranged in the sequence of the number of parts to be mounted, and the priority order is determined. At next step 54, distribution center coordinates (X, Y) of electronic components of every kind on the circuit board are determined as the mean of the X-coordinate and the mean of the Y-coordinate on the basis of the coordinates data of each electronic component. At step 55, according to the priority order by the number of parts to be mounted, the arrangement position of each electronic component is determined according to the distribution center coordinates (X, Y). The arrangement position of the electronic component low in the priority order is, if the arrangement position corresponding to the distribution center coordinates (X, Y) has been already assigned, determined at the closest arrangement position in the neighboring blank position.
In the prior art, electronic components of the kind larger in the number of components to be mounted are preferentially assigned with the arrangement position, and the preferentially assigned position is based on the distribution center coordinates. Accordingly, the prior art has a certain rationality for shortening the required moving distance of the mounting head. However, the following problem was involved when determining the priority order of arrangement position among electronic components nearly same in the number of components to be mounted. That is, when the distribution center coordinates are nearly same and the arrangement position is identical, supposing one kind is slightly larger in the number of components to be mounted but has a wide distributed state of mounting positions of the electronic components belonging to the same kind, while the other is slightly smaller in the number of components to be mounted but is mutually close in the mounting positions of electronic components belonging to the same kind and hence narrow prior has a distributed state, in the prior art, the arrangement position is preferentially determined for the electronic components belonging to the kind having a wider distributed state. When the arrangement position is determined in this way, it is general that the effect is larger in the distributed state than in the number of components to be mounted, and as a result, as compared with the case of determining oppositely, the moving distance of the mounting head is longer, and the mounting efficiency is lowered.